GALAPAGOS TOKTOISES 305 



Tres Marias, Galapagos and Chiloe islands. Beyond this 

 centre of distribution there are only two remote stations, one 

 in Madagascar, the other on the Fiji islands. We could not 

 have a better example of discontinuous distribution, which, 

 as Dr. Wallace has always urged, is a proof of antiquity. 

 Lastly, the Galapagos snake belongs to the ancient family 

 Colubridae, which also includes Tropidonotus, a genus 

 specially alluded to (pp. 128 and 222). 



In spite of these facts, Mr. Heller * expresses the opinion 

 that the archipelago is mostly of Tertiary age, and that the 

 fauna has been chiefly derived from material carried by ocean 

 currents. 



Still another expedition has lately been sent to the archi- 

 pelago by the California Academy of Sciences. Dr. Van 

 Denburghf who was asked to report on the reptiles feels quite 

 convinced that the islands must all at some former period 

 have formed parts of a single land-mass. In a letter which he 

 addressed to me, he implies that several species of snakes 

 inhabit the islands. He states that "the closest relatives 

 of the serpents of the Galapagos archipelago are native to the 

 Bahamas, Greater and Lesser Antilles, Costa Eica and the 

 whole of South America. This being true, the snakes of these 

 localities must have had a common origin. Either the West 

 Indian and Galapagos snakes have been derived from South 

 America, or else all must be descendants of species occupy- 

 ing a great central land-mass which has sunk below the level 

 of the sea, leaving mere remnants in Central America, 

 northern South America, the Antilles and the Galapagos. 

 Either view implies a former land connection and a con- 

 tinental origin of the Galapagos ophidian fauna. 1 cannot 

 bring myself to share the opinion of those who believe that 

 the fauna of the Galapagos has reached these islands by the 

 more or less accidental agency of the winds and ocean 

 currents." 



When Dr. Stearns J reported upon the land and fresh-water 

 snails inhabiting the Galapagos archipelago, he alluded to one 



* Heller, E., " Hopkins-Stanford Expedition : Eeptiles," pp. 46— 48. 

 t Denburgh, John Van, " Preliminary Descriptions of Land-tortoises," 

 p.l. 

 X Stearns, E. E. C, " MoUusk-f auna of the Galapagos," pp. 359—370. 



L.A. X 



